1. Technical Field
The present disclosure relates to a light enhancing structure for a light emitting diode, especially relates to a light enhancing structure for a top emitting light of a light emitting diode.
2. Description of Related Art
Light emitting diodes have been attracted high attentions in the lighting industry. Characteristics of the light emitting diodes such as its low energy consumption, high lighting efficiency and longer life time, are superior to conventional lighting devices. The light emitting diode can be manufactured by a photolithography technology thereby can be highly integrated to a manufacturing process of an IC. Therefore, in the modern electric device, it commonly utilizes light emitting diodes as a backlight source.
Light emitting diode can be classified into two kinds, organic light emitting diode and inorganic light emitting diode. Owing to native limitation on the material of the organic light emitting diode, the lighting efficiency and the reliability thereof are inferior to that of the inorganic light emitting diode. Therefore, the inorganic light emitting diode is more commonly used in the field of solid lighting.
Conventionally, an inorganic light emitting diode is formed by multiple semiconductor layers. In a basic inorganic light emitting diode structure, a p-type semiconductor layer and an n-type semiconductor layer are connected for forming a p-n junction. When the inorganic light emitting diode is driven by a current, electrons are provided from the n-type semiconductor layer and holes are provided from a p-type semiconductor layer. The electrons and the holes are combined M the p-n junction, thus a plurality of lights are generated.
In the aforementioned inorganic light emitting, diode, the lights generated from the p-n junction include a top emitting light and a side emitting light. However, owing to the geometric structure and the manufacturing process, to light intensity of the top emitting light is larger than a light intensity of the side emitting light. Therefore, enhancing the light intensity of the top emitting light is a critical problem.
For enhancing the light intensity of the top emitting light, various technologies have been developed. One method is to add an extra reflecting structure to the original light emitting diode structure. Thus, the side emitting light is reflected toward a light direction of the top emitting light, and the light intensity of the top emitting light is enhanced. Another method is to change the structure of the light emitting diode, thus the lights generated from the p-n junction can be collected toward the light direction of the top emitting light.
However, in the light enhancing method of the aforementioned examples, either the added reflecting structure or the changed light emitting diode structure have drawback of complicated manufacturing process, and extra equipment are required, therefore the manufacturing cost is high.